Overview of EU DEMO design and R&amp;D activities

Federici, G.; Kemp, R.; Ward, D.J.; Bachmann, Christian; Franke, Thomas; Gonzalez, S.; Lowry, C.; Gadomska, M.; Harman, Jon; Mészáros, B.; Morlock, C.; Romanelli, M.; Wenninger, R.

doi:10.1016/j.fusengdes.2014.01.070

Cited by 284 publications

(206 citation statements)

References 13 publications

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“…Below we present the results of calculations for the "standard" set of the input parameters taken from the European DEMO project: 9 Figure 3 shows the radial profiles of the SOL averaged values for the particle densities of molecules, hn m i, all atom species, hn a i, and plasma, hni; the densities of sources for cx atoms, hS cx i, and charged particles, hS ion i; the temperatures of electrons, hT e i, and ions, hT i i. The results of calculations with the kinetic and diffusion descriptions of c-x atoms are displayed by dashed and solid curves, respectively.…”

Section: Results Of Calculationsmentioning

confidence: 99%

“…However, the validity of the assumptions and steps described above are not strictly proved. Therefore, we deduce here the particle flux density in a diffusion approximation directly from the velocity distribution function for c-x atoms given by the relations (8) and (9). By taking into account that x and U x are uniquely related to each other, we introduce the variable…”

Section: Diffusion Approximationmentioning

confidence: 99%

“…By substituting the expansion above into the relations (8) and (9), one can easily perform the integration over U y . By neglecting exponentially small terms proportional to exp ðÀU x =jV x jÞ, we get…”

Section: Diffusion Approximationmentioning

confidence: 99%

“…The averaging of plasma transport equations along the flux surfaces in the SOL main fraction and the assessment of the loss terms due to particle and heat flows towards the divertor are performed in Section III. In Section IV computations are done for the input parameters from the European DEMO project 9,10 and the results obtained with either kinetic or diffusion description of c-x neutrals are compared. It is demonstrated that practically for all characteristics of interest, the diffusion approximation is sufficiently satisfactory.…”

Section: Introductionmentioning

confidence: 99%

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Scrape-off layer modeling with kinetic or diffusion description of charge-exchange atoms

Tokar

2016

Physics of Plasmas

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Hydrogen isotope atoms, generated by charge-exchange (c-x) of neutral particles recycling from the first wall of a fusion reactor, are described either kinetically or in a diffusion approximation. In a one-dimensional (1-D) geometry, kinetic calculations are accelerated enormously by applying an approximate pass method for the assessment of integrals in the velocity space. This permits to perform an exhaustive comparison of calculations done with both approaches. The diffusion approximation is deduced directly from the velocity distribution function of c-x atoms in the limit of charge-exchanges with ions occurring much more frequently than ionization by electrons. The profiles across the flux surfaces of the plasma parameters averaged along the main part of the scrape-off layer (SOL), beyond the X-point and divertor regions, are calculated from the one-dimensional equations where parallel flows of charged particles and energy towards the divertor are taken into account as additional loss terms. It is demonstrated that the heat losses can be firmly estimated from the SOL averaged parameters only; for the particle loss the conditions in the divertor are of importance and the sensitivity of the results to the so-called “divertor impact factor” is investigated. The coupled 1-D models for neutral and charged species, with c-x atoms described either kinetically or in the diffusion approximation, are applied to assess the SOL conditions in a fusion reactor, with the input parameters from the European DEMO project. It is shown that the diffusion approximation provides practically the same profiles across the flux surfaces for the plasma density, electron, and ion temperatures, as those obtained with the kinetic description for c-x atoms. The main difference between the two approaches is observed in the characteristics of these species themselves. In particular, their energy flux onto the wall is underestimated in calculations with the diffusion approximation by 20%–30%. This discrepancy can be significantly reduced if after the convergence of coupled plasma-neutral calculations, the final computation for c-x atoms is done kinetically.

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Section: Results Of Calculationsmentioning

confidence: 99%

Section: Diffusion Approximationmentioning

confidence: 99%

Section: Diffusion Approximationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Scrape-off layer modeling with kinetic or diffusion description of charge-exchange atoms

Tokar

2016

Physics of Plasmas

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“…The study of a credible design point for a DEMO device [1] is devoted to the demonstration of the capability of a tokamakbased fusion reactor to deliver electricity to the grid. The assessment of the concrete possibility of an efficient control of the main parameters of the plasma scenario and the determination of the technical figures of the subsystems are essential parts of this study.…”

Section: Introductionmentioning

confidence: 99%

Diagnostics and control for the steady state and pulsed tokamak DEMO

Orsitto¹,

Villari²,

Moro³

et al. 2016

Nucl. Fusion

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The present paper is devoted to a first assessment of the DEMO diagnostics systems and controls in the context of pulsed and steady state reactor design under study in Europe. In particular, the main arguments treated are: (i) The quantities to be measured in DEMO and the requirements for the measurements; (ii) the present capability of the diagnostic and control technology, determining the most urgent gaps, and (iii) the program and strategy of the research and development (R&D) needed to fill the gaps. Burn control, magnetohydrodynamic stability, and basic machine protection require improvements to the ITER technology, and moderated efforts in R&D can be dedicated to infrared diagnostics (reflectometry, electron cyclotron emission, polarimetry) and neutron diagnostics. Metallic Hall sensors appear to be a promising candidate for magnetic measurements in the high neutron fluence and long/steady state discharges of DEMO.

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Fusion Energy Harnessing, Reactor Technology, and Sustainability

Dobran¹

2017

Kirk-Othmer Encyclopedia of Chemical Technology

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The energy produced from the controlled thermonuclear fusion of hydrogen isotopes can replace fossil fuels and become a sustainable energy source. The fusion of deuterium and tritium has been achieved in several experimental reactors where the plasmas are confined with magnetic fields and there is high optimism that this will also be achieved with laser and ion beams. The plasma confinements and reactor technologies of tokamaks and stellarators are paving the way for building demonstration fusion reactors and subsequently commercial fusion power plants. Following a review of the magnetic and inertial plasma confinement concepts, the reactor technologies that implement these concepts are assessed for producing sustained plasma ignition, external plasma heating, control of plasma instabilities, developments of low‐activation and high strength materials, coolants for removing fusion energy from the reactor, and breeding tritium in the blanket of the reactor for achieving fuel self‐sufficiency. Sustainability of fusion energy requires the long‐term availability of fusion fuels and reactor components materials, social acceptability, minimization of waste products, and safe operation of fusion power plants. These and other issues considered strongly suggest that the fusion energy will become a viable energy source for human development.

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Overview of EU DEMO design and R&D activities

Cited by 284 publications

References 13 publications

Scrape-off layer modeling with kinetic or diffusion description of charge-exchange atoms

Scrape-off layer modeling with kinetic or diffusion description of charge-exchange atoms

Diagnostics and control for the steady state and pulsed tokamak DEMO

Fusion Energy Harnessing, Reactor Technology, and Sustainability

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